Oil-proof electrical insulating compound and method of making-same.



JOHN moon KESSLER, JR

., or sr. Louis, MISSOURI.

OIL-PRO0F ELECTRICAL INSULATlNG COMPOUND AND METHOD OF MAKING SAME.

Specification of Letters Patent.

Patented March 12, 1907.

' Application filed June 29, 1906. Serial No 324,026.

T0 or, whom it may concern:

Be it known that 1', JOHN JACOB KESSLER, In, a citizen of the United States, residing at St, Louis, and State of Missouri, have in vented certain new and useful Improvements in Oil-Proof Electrical Insulating C mpounds and Methods of Making Same, of which the following is a specification.

The object of my invention is to produce an oil and water proof compound having a high insulating resistance against electric currents, the com ound-being especiall designed, for use in t e production of insu ated electric coils and of such character as to remain rigid and strong at high temperatures.

My improved compound is produced in the following manner: Linseed-oil or other similar oil or a varnish having such oil as a constituent is intimately mixed with a flaky powdered or fibrous non-conducting mire eralsuch, for instance, as mica, limestone, soa stone, or asbestos-a sufficient quantity to t. e oil or oil-varnish being used to make a paste. This mixture is then dried in any suitable manner and the dried mass ground in a mill witha volatile oil, such as naphtha pr benzol, which will dissolve, partially dis- ,splve, or soften the dried oil or oil-varnish. The result is a homogeneous paint or enamel which becomes hard and dry upon evaporation of the solvent, the last traces of which may be expelled by baking in an oven such as is commonly used fordrying purposes in -the electrical arts. In order to make the dried mass more flexible or tougher, there'may be added tothis paint or enamel a small amount of fresh varnish or varnishgum.

The compound described when applied to coil, either as it is being wound or after it has been wound, hardens as the volatile oil evaporates and forms, with the wire,.a solid oil-proof mass where all chemical action has been practically eliminated.

'l. he dired mixture oi the non-conducting mineral and oil or oil-varnish may be ground in a mill withc. t the presence of the volatile i oil, and such oil mixed therewith at the time of use, if desired; but I- refer to make the complete preparation att e time of grinding, as a'more homogeneous compound is' obtained. V T

Where it is desirable that the compound shall possess great hardness and little elasticity, l have found that thirty-four parts of dry linseed-oil varnish and sixty-six parts quantityoi a mixture of equal parts of woodalcohol and benzol to produce a paste makes a satisfactory mixture. If less hardness and more elasticity is dpsired, the proportion of the dry'linseed-oil varnish is increased and the proportion of whiting decreased. 'lhe desirable proportion for this purpose is sixtysix parts of the dry varnish and thirty-four parts of \vhiting again using a suflicient quantity of the solvent composed of equal par ts ol' Wood-alcohol and benzol to produce the desired paste.

I claim as my invention 1. An insulating compound comprising a mixture of a non-conducting mineral and oil, which has been dried and ground.

2. An insulating compound comprising a mixture of a non conducting mineral and linseedoil, which has been'diied and ground.

3. An insulating compound comprising a mixture of anon-conducting mineral and linseed-oil varnish, which has been dried and ground.

' 4. An insulating compound comprising a mixture of a non-conducting mineral and oil, which has been dried and ground, and a volatile oil. Y

- 5. An insulating compound comprising a mixture of a non-conducting mineral. and linseedoil, which has been dried and ground,

and a volatile oil. l 6. An insulating compound comprising a mlXl/UIB of a non-conduot1ng mineral and linseed-oil varnish, which llas been dried and ground, and a VOlatllQ Oll.

7. That improvement in the art of produc- I 'ing insulating compounds which consists in mixing a non-conducting mineral with an oil, hardening the mixture, grinding the mixture, and mixing therewith a volatile oil with the ground mass.

8. Thatimprovcment in the art of producinsulating compounds which consists in forming a mixture of a non-conducting mineral and linsced oil, dryi-n'gthe mixture, and thereafter grinding the dried mixture gethcr with a volatile oil. I

9. That improvement in the art of producing insulating compounds which consists in,

forming a mixture of a non-conducting mineral and-oil, drying the mixture, and thereafter grinding the dried mixture together with a volatile oil. I

10. That improvement in the art of producing electrical insulating compounds which consists in forming a mixture of a non-eondrying the mixture, and thereafter grinding ducting mineral and oil varnish, drying the the dried mixture with a volatile oil. V I9 mixture, and thereafter grinding the dried In witness whereof I have hereunto set m mixture with a volatile oil. 1 4 hand and seal at St. Louis, Missouri.

11. That improvement in the art of pro'duc- JOHN JACOB KESSLER, JR. [1 5.]- ing electrical insulating compounds which Witnesses: consists in forming a mixture of an inert non- ARTHUR VOGEL, conducting mineral and linseed-oil varnish, I JOHN WJBURIAN. 

